Migrate to standard integral types.

The following changes are done via find/replace.
* int8 -> int8_t
* int16 -> int16_t
* int32 -> int32_t
* int64 -> int64_t

The aliases were removed from snappy-stubs-public.h.

PiperOrigin-RevId: 306141557

snappy.h

@@ -40,6 +40,7 @@
 #define THIRD_PARTY_SNAPPY_SNAPPY_H__
 
 #include <cstddef>
+#include <cstdint>
 #include <string>
 
 #include "snappy-stubs-public.h"
@@ -63,7 +64,7 @@ namespace snappy {
   // Also note that this leaves "*source" in a state that is unsuitable for
   // further operations, such as RawUncompress(). You will need to rewind
   // or recreate the source yourself before attempting any further calls.
-  bool GetUncompressedLength(Source* source, uint32* result);
+  bool GetUncompressedLength(Source* source, uint32_t* result);
 
   // ------------------------------------------------------------------------
   // Higher-level string based routines (should be sufficient for most users)